1. I. I.Phylogeny and Systematics A. A.Cladistics Analysis of phylogenetic relationships based on shared characters Characters may be primitive or derived Clade = Group of species that includes ancestral species and all descendents Cladogram – Diagram that illustrates evolutionary relationships among clades Outgroup – Used to distinguish primitive from derived characters

3. I. I.Phylogeny and Systematics B. B.Relationships among Taxa Taxa may be categorized according to how they reflect evolutionary relationships

4. Fig. 26.10

5. I. I.Phylogeny and Systematics C. C.Traits in Classification Establishing relationships among taxa requires careful examination of characters Ancestral characters = plesiomorphies Shared ancestral characters (symplesiomorphies) unite descendants of a single ancestor into a monophyletic clade Ex: Vertebral column in vertebrates Derived characters = apomorphies Shared derived characters = (synapomorphies) unite derived clades and separate them from ancestral clades Ex: Amniote egg and feathers in reptiles/birds and birds

6. Fig. 26.11

7. II. II.Ecology “Ecology” from Greek “Oikos” (house) Interactions among groups of organisms and between organisms and physical environment Includes abiotic and biotic components

8. Fig. 52.17

9. Physiological Behavioral Evolutionary Fig. 52.2